The present disclosure relates to a control device, a control method, and a control program.
Recording and playback devices that use optical disks as recording media are widely used, and the optical disks that are used include read-only disks, write-once disks, rewriteable disks, and the like.
The read-only disk may be, for example, a ROM type disk in which information is recorded in the form of embossed bits. The write-once disk is a disk that uses a dye change film in its recording layer and that records information by using a laser to form dye change pits (marks). Information can be written to it only once. The rewriteable disk is a disk that uses a phase change film in its recording layer and that records information by using a laser to form phase change pits (marks). Information can be rewritten to it. The various types of disks are used for various types of uses, according to their respective characteristics.
Incidentally, performing laser output control during recording is effective in recording devices for the write-once disk and the rewriteable disk. This technology is also known as Optimum Power Calibration (OPC).
OPC is particularly effective with respect to unevenness in the manufacture of the disk (unevenness in the recording layer), a skewed state (tilting of the optical disk in relation to the optical axis), and the like. For example, during recording, the shape of the laser spot and the distribution of energy within the spot vary due to the manufactured unevenness in the recording layer and the skewed state, causing variation in the pit formation performance. It is therefore desirable to adjust the laser output during recording in accordance with these factors, such that the pit formation performance can be maintained. For example, OPC technologies are disclosed in Japanese Patent Specification 2764965, Japanese Patent Application Publication No. JP-A-4-10237, and Japanese Patent Application Publication No. JP-A-6-76288.